An Electrically Decoupled Lateral-Axis Tuning Fork Gyroscope Operating at Atmospheric Pressure

In this paper, a bulk micromachined lateral axis TFG (tuning fork gyroscope) with torsional sensing comb capacitors is presented. Both driving and sensing modes of the gyroscope are dominated by slide film air damping, then it can work even at atmosphere. Novel driving comb capacitors are used to electrically decouple the mechanical coupling from sensing mode to driving mode. The process for this gyroscope is also compatible with z-axis gyroscope, which makes it potentially to realize low coast monolithic MIMU (miniature inertial measurement unit) without vacuum packaging. The TFG was fabricated and tested at atmosphere. The sensitivity is 17.8 mV/deg/s while the nonlinearity is 0.6%. The bias stability is 0.05deg/s (1sigma) and the noise floor is 0.02deg/s/Hz^1/2.